Variable speed drive with multiple belts



Sept. 16, 1941, D. HEYER 2,256,114

VARIABLE SPEED DRIVE WITH muufnpn BELTS Original Filed April 22, 1933 'V '2 Sh eets-Shaet 1 I VENTOR, v

Sept; 16, 1941. D, HQER 2,256,114

VARIABLE SPEED DRIVE WITH MULTIPLE BELTS Original Filed April 22, 1933 i w r w.

s sasssswsss INVEN TOK 0/? Z 2612 ZZZ/i) AT TO KN BY 2 Sheets-Sheet 2 Patented Sept. 16, 1941 VARIABLE SPEED DRIVE WITH MULTIPLE BELTS Don Heyer, Los Angeles, Calif., assignor to U. S.

Electrical Motors, Inc.,

corporation of California Original application April 22, 1933, Serial No. 667,379. Divided and this application April 22, 1940, Serial N0. 330,835

8 Claims.

This invention relates to a variable speed drive .utilizing pulleystructuresof variable effective diameters.

This application is a division of an application filed April 22,1933, under Serial 'No. 667,379, and entitled Variable speed drive with multiple belts, in the name of Don Heyer.

In such variable speed devices, use is made of pullely structures, each having a pair of relatively axially movable members, having inclined opposed faces. The belt is in frictional contact with these faces, and as the faces move together,

the belt must move radially outwardly, thus causing the effective pulley diameter to increase. Conversely when the sections move apart, the belt moves inwardly of the pulley,v and the diameter is decreased. I

Such drives in general are now well-known. It is one of the objects of the present invention to improve in general, this type of drive.

It is apparent that for transmitting heavy power, a heavy pulley structure must be provided, or else a number of pulleys may be used, having a multiple belt arrangement. It is another object-of the invention to provide a compact and inexpensive device utilizing multiple belts.

In utilizing such multiple belts and pulleys, it

is apparent that the individual pulley structures, making up the belt arrangement, should be capable of accurate and simultaneous adjustment, so thatthey are all of the same effective diameter at all points of adjustment. other object of myinvention to make it possible to cause such adjustment, in a simple.and easy manner.

Since the power delivered by a mechanism is a product of speed and torque, it is apparent that for a given power output, the torque can be kept at a small value if the speed is high. The low torque is useful in pulley drives of this character, because then the forces involved are relatively small.

Accordingly, an inexpensive design can be used if the pulley devices transmit the power at high speed. Most electric motors operate at a high speed, such as 1800 revolutions per minute, but the load is often of such a nature that -a very low speed is desired, with heavy torque characteristics. It is another-object of the invention so to correlate the variable speed pulley devices with such a system, as to provide the requisite speed andtorque output, while the adjustable pulley .devices are themselves operated at an 'eflicient, high speed.

It is still an- I Los Angeles, Calif., a

This can be accomplished by connecting the motor shaft directly to the variable pulley struc-' tures, and by reducing the resultant speed of the pulley transmission by appropriate gearing, connecting the system to the load. I

This invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of several embodiments of the invention. For this purpose there are shown a few forms in the drawings accompanying and forming part of the present specification. I shall now proceedto describe .these forms in detail, which illustrate the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention appended claims.

- Referring-to the drawings:

Figure l is a view, mainlyin horizontal gether withia diagrammatic showing of the fluid control mechanism; o

' Fig. 2 is a side view of the apparatus, with the cover member removed, and taken from the plane 22 of Fig. 1; and

Figs. 3 and 4 are sectional views showing mod- -ing from a source of power, such an-electric motor 3. This electric motor is arranged to be supported adjacent one wall of a casing 4, which is appropriately provided with the extending flange 5 for the accommodation 'of the outer frame of motor 3.

Casing 4 serves conveniently to form a housing for substantially all of the parts of the system. Shaft l transmits power to shaft 2 by the aid of a. plurality of flexible wedge shaped belts 6 I and l, and a plurality of adjustable pulley structures 8, 9, l0 and II. Each of the adjustable pulley structures includesa pair of 'relatively' axially movable sections having opposed inclined faces. As the faces are brought together the belt is urged upwardly on the incline formed between the two faces and the efiectivepulley I diameter is increased. When it is desired to decrease the fieective pulley diameter, the sections are permitted to move apartdn response to I the thrust exerted by the belt,

In the present instance each of the pulley is best defined by the section, of one embodiment of the invention, to-

' able sections it and II are each structures 3 and 3 has an axially fixed section i2 or l3. The axial anchoring in this instance is provided as by the aid of studs l4, l extending through the hubs of. sections l2 and I3 and through the shaft I. The studs l4 and I5. thus serve to provide a drive connection between the sections i2, i3 and the shaft. The corresponding axially movprovided with comparatively long hubs l8 and i9. These long hubs respectively telescope inside of the hub of the stationary sections and are freely slidable in the annular space formed between the shaft I and the hubs of the fixed sections. In order to key the movable sections I61 and I] to the shaft I, while at the same time to permit this axial movement, these hubs l3 and I9 are prosystem indicated in vided with slots and 2! through which the studs l4 and I3 respectively pass.

.It is also to be noted that the end surface of hub I! contacts with the section It. In the position shown in Figure 1 the pulley structures 8 and I are substantially at-their minimum effective diameter settings. In order to increase the effective diameters simultaneously and equally, it is merely necessary to urge pulley section 41 toward the left. This exerts a force on pulley section It also to the left. For decreasing the effective pulley diameters, pulley section ll can be moved. to the right: and although pulley section it is not positively connected to the hub l3, yet the force exerted by belt 8 will move pulley section II to the right and keep it in contact with the endv surface of hub l9. It is apparent that section It is constrained against free axial movement. by with belt I and hub ll.

The manner in which section II can be axially adjusted is susceptible of wide variation. In the present form a hydraulic system is provided, as

in the prior application hereinbefore referred to.-

To effect this result the movable section II has a hub structure 22 extending toward the right over the shaft I. This hub structure'can carry the inner race of a ball thrust-bearing 23, which is held tightly by one or more clamp inner race nuts 24, threaded on the end of hub 22. The outer race of the ball bearing structure istightly iheld inside of an axially movable support which is of cup shape, and which has a cover member 2,3 for preventing escape of lubricant I thrust ball bearing 23 movable support is to the left.

I tight relation a The inner end of the 1 tight cover member tion 33 for the accommodation of a compression 1 spring 33.

I and acts on the right hand end of v be used to exert a force urging from the bearing structure, as well as for preventing the ingress of foreign matter thereto.

. which are carried on shaft being in contact both spective pulley structures, the left hand sections The movable support 25 is constrained against rotation inside of a guide '21, as by the aid of a key 23 acting as a spline'in a keyway 30, provided on an inner periphery of a. stationary 1 member 21. Member 21 is provided with a flange II by the aid of which it may be fastened to the 1 wall of easing 4.

It is apparent as thus far described, that the serves not only to impart an axial force upon the pulley section II, but also acts .to journal the revolving structure.

Fluid pressure isused to urge the axially Thus there is a cover member 32 to which is joined in fluid corrugated metal bellows 33. metal bellows has a fluid 34 with a reentrant por- Fluid fills the corrugated bellows 33 33 and may support 23 to the left; by expansion of the bellows 33. The

2,256,114. which are carried by shaft l,

fluid is supplied through a conduit 31 connect ing to a controllable or adlustable volume chamber 38. With the system 33, 31, 33 filled with incompressible liquid, such as oil, it is apparent that bellows 33 can be made to expand and contract respectively by the contracting and expanding of the variable volume chamber 38. The adjustable volume chamber 38 can be of the piston and cylinder type, or the metal bellows type, and it can be controlled by any usual mechanical general by the rectangle 38. Since the fluid control system can be substantially the same as that disclosed in the prior application referred to, further details of its mode of. operation are considered unnecessary. It is sufficient to say that upon expansion of bellows 33 both the movable sections i8 and II are urged to increase the effective pulle'y diameters simultaneously and equally. Upon a con traction of bellows 33the sections 18 and II: are permitted to move toward the right to-decrease the effective pulley diameters. A

The adjustable pulley structures III and II '2 have substantially the same mode of operation as the pulleys .just described. Pulley structure G0, which cooperates with pulley structure 8 has a right hand fixed section 40 and a left hand' adjustable section 4|. has a fixed pulley section 42 and an adjustable section 43, and cooperates with pulley structure The arrangement is such that when the effective diameters of structures 8 and 9 are increased the effective diameters of structures Ill and II are correspondingly decreased, whereby the belts 6 and 'I are maintained in proper tight- .ened condition. Furthermore, in order to keep the belts 6 and I in alignment between the re- 4[ and 43 form the adjustable sections. In this way, if the adjustable sections 4! and 43 are moved to the left to decrease the effective pulley diameters the movable sections l3 and II are also moved to the left to increase the respective pulley diameters. The belts 8 and I then move up on the faces of fixed pulley sections l2 and I3 and down the faces of fixed pulley sections 40'and 42, staying in properaligned position during this adjustment.

Pulley structures l0 and H are indicated as having maximum effective pulley diameters. As before, the fixed sections 40 and 42 are anchored to the shaft 2 as by the studs 44 and 43 which pass through the shaft and through the hubs of these sections. The movable pulley sections 4| and 43 are each provided with the slotted hub 46 and 41 telescoping between the shaft 2 and the fixed sections to, 42, Motion of the two sections 4| and 43 is caused to be in unison by having the end face of hub 48 contact with the section 43.

Control ofthe effective pulley diameters of structures It and II iseffectedin amanner similar to that described in connection with structures 8 and 9. Thus the hub-43 of the left hand movable pulley section 4| carries the inner race of a thrust ball bearing 49. The outer race is carried by the axially movable cup 50 splined to a stationary support 5|. Thisstationary support 5i can be fastened, as by the aid of a flange 52, to a. wall of the casing 4. A metal bellows 53 shown in an expanded'position, is fastened to the cover member and acts upon the compresslon spring 55. This compression spring exerts a. force upon the axially movable support 30.

Similarly the adjustable pulley structure ll Shaft 2 is supported by the thrust bearings 49 at the left hand end. At the right hand end the rotating structure is supported by a" thrust ball bearing structure 56. The inner race of this ball bearing structure is fastened to the hub of the 5 .stationary section 42; and the outer race is fastened into an aperture 51 formed in the wall of casing I. A cover 58 serves to retain the outer race in place as well as to prevent the ingress of foreign matter to the bearing.

The fluid control for the pulley structures l0 and II is provided by the adjustable volume chamber 59 connected to bellows 53 by the aid of a conduit 60. The common control 39 can be outer race of a ball bearing I2. The inner race is, I

held against a shoulder on the shaft 6|.

I0 and 12 arrangements aremade to machine the inner wall of pocket 69 at the same time as a shoulder I3 on flange 65. This shoulder I9 extends nearly around the axis of shaft II, as in-' dicated in Fig. 2, and serves as a guide for the correspondingly machined projection 14 on cover 66. If shoulder 13 and the inner periphery of pocket 69 be simultaneously machined they are In order to facilitate lining up the, bearings accurately aligned with respect to a common censo arranged that it acts simultaneously on both 5 chamber 38 and 59 to provide simultaneous adjustment of all four adjustable pulley structures. Thus when bellows 53 is expanded bellows 39 is contracted, causing all of the movable sections I6, I1, 4| and 43 to move to the right, thereby causing the effective diameters of structures 8 and 9 to decrease and those of structures I0 and II to increase. Y

In most instances the speed of an electric moparts are assembled as shown in Fig. 1 certainty that both bearings I0, 12 will be corter.' Similarly, if the inner periphery of boss II and the projection I4 be simultaneously. ma-

chined then these two elements are also in accurate axial alignment. Accordingly, when the there is a rectly aligned.

It is possible to. provide a common fixed member for providing the fixed sections of both pulv ley structures. One such arrangement is illustrated in Fig. 3. In this case the shaft 94 has.

' flxed thereto an intermediate, stationary member tor, such as motor 3, is too high even when reduced by thevariable speed pulley devices to operate the usual form of load, which requires a comparatively heavy torque and slow speed. The ratio of maximum to minimum speed that can be obtained by the adjustable pulley structures is usually of the order of 3 to, 1, but the resultant speedsof shaft 2 would still be too high for effective use. Since it is advisable to operate belts 6 and I at as low a torque as possible, the

present arrangement as is apparent, provides a comparatively high speed, low torque, load to be transmitted by these belts.

In order to make the power available for heavy torque loads a supplemental reduction gearing be pulled toward the right to increase the effective is provided by the driven shaft 2 and a load shaft 40 6I. This reduction gearing may include a pinion 62 fastened to shaft 2 and a driven gear 63 fastened to shaft 6|. The manner in which these gears are supported will now be described.

Pinion 62 has an axial extension 64 which is pressed tightly into shaft 2 purposely made hollow. Stud 45 also passes through the extension 64 and anchors it positively in place. Pinion 62 as is apparent from Figs. 1 and 2 extends on the It is, however, in-

outside of casing proper. closed by the aid of flange 65 and cover '66 in a supplemental housing 61. This supplemental housing encloses the gears 62 and 63.

At times it may be desirable to remove pinion 62, as for replacement or repairs. This can very easily be effected by the aid of fluid pressure. Thus hollow shaft 2 can be filled with an incompressible fluid, such as oil, and this incom- 'pressible fluid can be, retained by the aid of a I left hand threaded plug 68 threaded'into the end of shaft 2. If it is desired to express pinion 62, stud l5 isflrst removed,and plugs ,usedto close the openings in shaft 2. Then plug 68 is screwed in as 'bya wrench. The resultant fluid pressures obtained inside of the hollow shaft 2 6 serve to move'extension 6| outwardly as a pis-' ton.-

Shaft 6I, to which gear 63 is fastened, is journalled for rotation in two places; in the left hand wall of casing 4 and in the cover 66. Thus the. left hand wall of casing 4 has a; pocket 69 ac- .commodating-the outer racefof ball bearing I0.

The inner'race is fastened to the shaft 6|. The

pulley diameter by the aid of a pair of pull rods I04 and I05. These pull rods extend in a general axial direction and pass through the fixed intermediate section 95. These pull rods can be pulled toward the right by any appropriate mechanism.

For example, they may be joined at their right hand end by a stud I 06 passing through shaft 94 which ismade hollow at the-right hand end and provided with slots I01.

While section I00 is moved to the right to increase the effective pulley diameters the sec tion 99 is positively moved to the left-to in crease the effective pulley diameters of the'elements 9'I99. To effect this result the adjustable section 99 has a hub I08 extending toward the right and slidable on the shaft 94. Extending in an axial direction from the end of the hub are'two studs I09 and H0, each having horizontal extension III or II2. As pull rods I04 and I05 are moved toward the right, a pair of levers H3 and H4 are rocked about their stationary pivots H5 and H6. These levers are provided with oppositely directed bifurcated arms respectively engaging extensions 1 II or H2, and

. pin III or H8 fixed in the pull rods I04 and cover 66 has. hub II which accommodates the I05. The stationary pivots H5. and H6 are supported by the aid of a collar 1 I9 fastened to the shaft 94, and having brackets I20 and I2I.

It is apparent that as pull rods I04 and I05 are moved to the. right, the section 99 is urged to, the left through the intermediary of levers H3 and H4, which act a's a reversingmechanism. v v

. In'case positive actuation of thetwo sections 99 and I00 is not desired, spring pressure can be used to move them in opposite direction. Thus a compression spring I20 may be inserted in the as by the aid of a stud 96. This member 95 mitted to expand.

= rod connectedhollow portion of shaft 94. At the right hand end itmay act against the stud I joined to the pull rods I04 and I05. At. the left hand end it can act against a I22 in shaft 94. It is apparent that spring I20 serves to urge stud I06 and pin I2I apa to the mechanical interlock provided'by the levers H3 and H4, it is rendered certain that this resilient force acts equally to move sections 00 and I00 equal distances but in opposite directions. 1 j. A simplified form of the type of mechanism shown in Fig. 3 is illustrated in Fig. 4. In this case'an intermediate stationary section I23 is fixed to a shaft I24, as by the aid of a set screw 125. The oppositely movable sections I20 and I21 are arranged on opposite sides of section I23. Section I26 can be urged toward the right as by the aid of a pair of splines I21 and I28. These splines are movable in keyways provided in the shaft I24 as well as through the hub of section 123. The right hand end of the splines carry a ,collar I29 fixed'to the splines. A compression spring I30 is coiled aroundthe axis of shaft I24 and-has its right hand end against the collar I29.

'Its left hand end engages the adjustable section I21, which is movable on the splines I21 and I28.

It is apparent that as the flexible belts ISI and I32'move outwardly the spring I30 is per- This expansion takes placelevenly so that collar I20 and section I21 are equal distances. Section I21 1 thus moves to the left; and collar I29, moving to 1 theright. causes the 1 to the right, which in the right. Thus both 1 creased. Conversely, 1 move inwardly toward and I21 are moved away 1 I23 and spring I30 is compressed, because collar 'l29 and section I21 move moved apart by splines I21, I28 to ,move

effective diameters are inwhen belts I3I and I32 the axis, both sections i26 from the fixed section toward each other. what is claimed is:

1. In a multiple belt variable ratio transmission device, a shaft, a pulley section fixed to the f shaft, said pulleysection havin'g inclined faces 1 on opposite sides, a pair of. movable pulley sec- 1 tions,.respectively on opposite sides of the fixed 1 section, each I of said movable pulley sections having an inclined face. opposed to the corre- 1 'spondihg inclined face of the fixed section, and

section for increasing the effective pulley diameters, comprising a pull to one movable section and passing through the other sections, and a pivoted Q lever connecting said pull rod to the other movable section.

2. In a multiple sion device, a shaft, a pulley section fixed to the shaft, said pulley section having inclined faces on opposite sides, tions, respectively on opposite sides of the fixed section, each of said movable pulley sections hav- 0 ing an inclined face opposed tothe corresponding inclined face of the fixed section, and means for simultaneously moving the movable sections toward the fixed section for increasing the effective pulley diameters,comprising a pair of pull rods connected to one movable section, a

' transverse rod connecting the pull rods and passing through a slot in the shaft, and. a pair of lervers, each'having a stationary axis and oppositely extending arms, one of the arms being assbpin I2 I fastened to 1 the hub of section 90 and passing through slots tive pulley diameters,

ing inclined face of ciated respectively with the pull rods and the other arm with the other movable section.

3. In a multiple belt variable ratio transmission device, a shaft, a pulley section fixed to the shaft, said pulley sectionhaving inclined faces on opposite sides, a pair of movable pulley sections, respectively on opposite sides of the fixed section, each of said movable pulley sections hav- 4. In a multiple belt variable ratio transmis- I sion device, means forming a plurahty of adjustable pulleys in common axial driving relation,

each turn urge section-I21 to u and driven shafts,'relatively means for simultaneously moving the movable j sections toward the. fixed and driving belts connecting said other pulleys belt variable ratio transmisa pair of movable pulley seceach pulley being movable section, and

elements to one of said elements to adjust the same to of said pulleys having relatively axially movable sections having opposed inclined faces, forming by relative axial adjustment, variable effective pulley diameters, one of the sections for formed by a member fixed to a common shaft, the other of the sections being movableaxially with respect to the corresponding fixed section, and means justingall the movable sections to increase the effective pulley diameters, including bars extending from each movable section to the next through an intervening fixed section, said bars being connected to said next section through a reversingmechanism.

5. In a variable ratio transmission, driving and driven shafts, relatively adjustable pulley ele= mentson one of said shafts, a rocker disposed between and operatively connected to said pulley elements for adjusting the same, to one of said elements to adjust the same. and to thereby impart a relative adjustment to the other pulley element through said rocker, and a driving belt operatively connecting said pulley elements with the other of said shafts.

6. In a variable speed transmission, driving elements on one of said shafts, a rocker disposed between and operatively connected to said pulley for adjusting the same, means coupled thereby impart a relative adjustment to the other pulley element through of other pulleys mountedon the other shaft for independent longitudinal movement thereon,

with said pulley elements.

1. In a multiple belt variable ratio transmission, a shaft, a pulley section on the shaft, having inclined faces on opposite sides, a pair of axially movable pulley sections respectively on opposite sides of the fixed section, each of said movable pulley sections having aninclined face opposed to the corresponding inclined face of the fixed section, a resilient member coaxial with the shaft and. having an end operatively connectend of said member and ing inclined faces on opposite sides, a' pair of for simultaneously ad-' means coupled adjustable pulley.

said rocker, a'plurality axially movable pulley sections respectively on opposite sides'of the fixed section, each of said Vmovable pulley sections having an inclined face opposed to the corresponding inclined face of the fixed section, a resilient member coaxial with 5 the shaft-and having an end operatively connected to one of said movable pulley sections, means forming a connection between the other end of said member and the other movable pulley section, whereby said sections are urged-in'epposite axial directions by said member, and means ineluding a lever pivotally supported on the shaft for causing the movements of said. sections to be equal in amounts and inopposite directions.

DON HEYER. 

